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ccdfits - convert an image to a fits file
ccdfits writes a fits file to disk.
The input must be in image(5NEMO)
format, the output will be in standard
format on disk.
An experimental version of this program that
uses the standard cfitsio(3)
library is known as ccdfitsio(1NEMO)
following parameters are recognized in any order if the keyword is also
To convert an image to unsigned 16 bit integers
use the following math:
- input file, in image(5NEMO)
format [no default].
- output file, will be in fits(5NEMO)
format [no default].
applied for scaling. Options are 16, 32 or -32. [default: -32].
- Scaling factors for CDELT keyword. If the second or third number is omitted,
it is repeated from the previous number. [default: 1,1,1].
- Scaling factors for intensity (should only be used for BITPIX > 0) [default:
- Name of your object/image [default: none].
- Comment using the COMMENT keyword. [default: none]
- Use CD matrix
instead of CDELT? [t/f]. Default: f.
- Blocking factor (multiplicity
of blocksize in terms of 2880 bytes) used when writing the fits file. [default:
- Reference map or cube (a fits file) from which the WCS is inherited.
It has to match the output cube which is created. Deprecated. By default
none is used.
- Use these pixels (2 or 3 need to be given, depending
if a map or cube is output) as reference pixel, instead of the one defined
in the reference map. By default not used.
- Use these values (2 or
3 need to be given, depending if a map or cube is output) as value at the
reference pixel, instead of the one defined in the reference map or defined
by the input. By default not used.
- Use these values (2 or 3 need to
be given, depending if a map or cube is output) as pixel increments, instead
of the one defined in the reference map or defined by the input. By default
- If no reference map used, this can be used to enforce
a more reasonable axis descriptor (RA/DEC/VEL) for astronomical data packages
which cannot handle theory data too well (e.g. miriad, karma etc.). We also
add CUNITn and BUNIT (albeit in JY/PIXEL). See also ccdsky(1NEMO)
smart scaling placing the object at a computed distance. [Default: f].
- Write dummy (NAXISn=1) axes too? If not, axes with length 1 are written
last. Default: t
- If used, this will be the value of NAXIS written
to the FITS file. Only useful of dummy=f and your FITS reader still cannot
handle dummy trailing axes. Default: not used.
- Number of dummy comment
lines to add to a fits header to test I/O routines. Default: 0
specified, testing if only that many dimensions need to be written.
- Select this image (1 being the first) to grab in an file with multiple
Image’s. [Default: 1]
a = "(a < 0 ? a+65536 : a)"
or using ccdmath:
ccdmath in=map1 out=map2 fie="iflt(%1,0,%1+65536,%1)"
A reference map (refmap=) does not have to be a full FITS cube. If the NEMO
routines are used, the header will suffice, since the data
is never needed. You can see scanfits(1NEMO)
scanfits in=cube.fits out=cube.fitshdr select=header
ccdfits ... refmap=cube.fitshdr ...
For historic amusement:
In the old days (somewhere before the
90s) there were actually software systems that could only directly read
FITS files from tape, not from disk. The disk-fits file must be written to
tape in ’raw’ format with a block length of 2880 bytes, which can be done
% dd if=fits.dat of=/dev/rmt0 obs=2880
Under VMS the tape has to be mounted with the blocksize:
$ MOUNT MT:/FOREIGN/BLOCK=2880/RECORD=2880
$ COPY MT: FITS.DAT
and the file on disk must be recorded to have a 2880 blocksize:
$ FIXATR/RFM=FIX:2880 FITS.DAT
In case FTP is used to transfer files, remember that FTP cannot handle
files with this format (some FTP’s at least). So it’s best to have them in
regular 512 byte blocks before moving, and at 2880 blocksize when using
programs such as DISKFITS in the VMS version of GIPSY.
You could also try
the following command procedure on VMS (Bob Hanisch, ST ScI):
$! FIXFITS filename
$! FIXFITS CONVERTs a file to the desired AIPSFITS disk format
$ create/fdl=sys$input: temp.dat
$! now convert - old fails some
$! convert/append ’P1’ TEMP.DAT
$! now convert - new method
$ copy ’P1’ TEMP.DAT/overlay
$ rename temp.dat ’P1’
$! clean up
$ purge ’P1’
~/src/pjt/image ccdfits.c ccdfits.1
29-apr-88 V1.0: created, calling WERONG fortran subroutines PJT
2-jun-88 V1.1: new filestruct, renamed wfits to ccdfits PJT
1-oct-90 V2.1: new fitsio and keyword comment=, scale now 1 PJT
11-oct-90 V2.2: added blocking= factor PJT
nov-92 documented the FITFITS VMS procedure PJT
dec-99 some more documentation PJT
apr-01 V3.0 reference map/pixel to inherit a WCS from PJT
6-may-02 V4.0b properly implemented dummy= PJT
4-jan-04 V5.2 docomented the recent changes to crval/cdelt/crpix= PJT
20-jun-09 V5.4 added select= to grab not the first image PJT
26-may-2016 V5.8 added CUNITn and BUNIT and better parameters for radecvel=true PJT
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